青蒿素与氯化血红素作用的荧光研究及分析应用

介绍了吡罗红为指示剂通过荧光降低法研究青蒿素与氯化血红素之间的相互作用.实验发现两者为酶和底物作用模型,作用位点为药物的过氧基团和氯化血红素活性中心的金属离子,其动力学催化常数Km,Vmax和Kcat分别为8.4×10-5mol· L-1,7.4×10-6mol·L-1·s-1及50.23 s-1,催化活性分别受去激活剂和高温影响.在最佳条件下,荧光降低值△F(F0-F)与青蒿素浓度在0.0～1.27×10-6mol·L-1范围内成线性关系,检测限为2.3×10-8 mol·L-1,该方法已用于测定血浆和尿液介质中的微量青蒿素.     

茜素红S荧光猝灭法测定壳聚糖含量

在pH 5.0的NaAc-HAc缓冲液中壳聚糖对茜素红S的荧光强度具有明显的猝灭作用,且猝灭程度F0/F与加入的壳聚糖浓度成线性关系,据此建立一种测定壳聚糖含量的荧光猝灭法。确定了最佳测定条件,线性回归方程为F0/F=-0.438 37 0.436 27c(mg·L-1),线性范围为0-16.667 mg·L-1,r=0.996,检测限为0.473 mg·L-1;平均回收率为100.60％,测定了样品中壳聚糖的含量,并考察了干扰因素对测定的影响。采用该方法可测定复杂样品中微量壳聚糖含量。     

壳聚糖包覆的CdTe量子点荧光猝灭法测定吉米沙星

以壳聚糖包覆的CdTe量子点为荧光探针,基于荧光猝灭法建立了吉米沙星定量测定方法。结果表明,体系的荧光强度与吉米沙星浓度在3.46×10-9～3.46×10-7 g.L-1范围内呈良好的线性关系(r=0.999 2),线性回归方程为F0/F=1.063 7+0.016 7c(g.L-1)。对2.77×10-7 g.L-1吉米沙星溶液进行7次平行测定的相对标准偏差为2.7%,基于荧光猝灭法相关理论证明了该相互作用过程为静态猝灭。本方法灵敏度高,检测线性范围宽,为吉米沙星定量测定提供了简便可靠的方法。     

氨基化碳量子点荧光猝灭法测定焦性没食子酸的研究

以葡萄糖为原料,通过一步水热法合成稳定性高的碳量子点,并用乙二胺使其表面氨基化。焦性没食子酸能使氨基化的碳量子点荧光明显猝灭,由此建立一种简便、高效检测焦性没食子酸的新方法。考察了缓冲体系p H、反应时间、反应温度等对焦性没食子酸测定的影响。结果表明,在pH=11.20的三酸缓冲溶液中,室温反应20 min时,体系的F0/F与焦性没食子酸的浓度呈良好的线性关系,其线性范围为4.0×10~(-6)~9.0×10~(-5)mol·L~(-1),相关系数r=0.997 4,检出限为3.5×10~(-6)mol·L~(-1)。该方法快速简便,适用于水样中焦性没食子酸的检测。     

利用L-半胱氨酸修饰的碳量子点作为荧光探针检测甘氨酸

甘氨酸是结构最为简单的氨基酸,以其为基石可以演变成各种复杂的人体所需的氨基酸,其本身不具有荧光特性。本文以柠檬酸为碳源,利用L-半胱氨酸作为修饰剂,合成了新的高荧光产率的碳量子点。经实验分析发现,合成的碳量子点的荧光能够被Pd(Ⅱ)显著猝灭,有趣的是,若在猝灭体系中加入适量的不具荧光特性的甘氨酸,可使猝灭的荧光恢复。基于碳量子点这种荧光"开-关"的模式,建立起一种快捷检测甘氨酸的新方法。在最优实验条件下,CDs-Pd(Ⅱ)体系检测甘氨酸的线性范围为9.0×10~(-7)~1.2×10~(-5)mol·L~(-1),检出限为1.1×10~(-7) mol·L~(-1)。     

油溶性CdSe量子点荧光探针直接检测农药水胺硫磷

基于农药水胺硫磷对油溶性CASe量子点荧光猝灭的现象,建立了一种简单、快速、直接检测农药水胺硫磷的新方法.在最佳实验条件下,油溶性CASe量子点的荧光猝灭程度与水胺硫磷浓度在2.30× 10-7～1.09×10-5 mol·L-1范围内呈较好的线性关系,相关系数为0.999 9,对水胺硫磷的检出限为1.1×10-7mol·L-1.本法已成功用于大米和小麦面粉样品中水胺硫磷农药残留的检测,加入回收率在93.3％～105.0％之间,结果满意.结合紫外-可见吸收光谱及时间分辨荧光光谱,探讨了水胺硫磷对油溶性CASe量子点荧光猝灭的机理.研究结果表明,水胺硫磷能有效改变油溶性CASe量子点的表面状态,增大了表面缺陷和非辐射重组的发生,从而使油溶性CASe量子点的荧光猝灭.     

Cu~(2+)参与的N-乙酰基-L-半胱氨酸修饰的CdTe量子点用于测定D-/L-青霉胺

以N-乙酰基-L-半胱氨酸作为修饰剂,合成了高荧光产率的CdTe量子点。在pH为7.80的磷酸缓冲溶液中,Cu~(2+)可以显著猝灭量子点的荧光,有趣的是,在猝灭体系中加入手性青霉胺(PA)可使其荧光恢复。因此基于量子点的荧光变化,建立了快速检测D/L-青霉胺的方法。在最优的实验条件下,NALC-CdTe QDs-Cu~(2+)体系测定青霉胺的范围为2.0×10~(-7)～4.0×10~(-6) mol·L~(-1),检出限为5.8×10~(-8) mol·L~(-1).将该法成功用于实际样品中检测D/L-青霉胺,取得了满意的结果。     

铜、钠和钼离子与牛血清白蛋白作用的荧光光谱研究

研究了铜、钠和钼离子对牛血清白蛋白(BSA)的荧光强度的影响.铜离子对牛血清白蛋白荧光有明显的静态猝灭现象,其离解常数为2.38×10-4mol·L-1.氯化钠对BSA溶液的荧光没有影响,说明生理盐水作为生物系统的体液对生命起到很好的保护作用.而钼离子在小浓度时对牛血清白蛋白荧光静态猝灭比较小,当钼离子浓度增加到8.4×10-3mol·L-1时,则呈现出雪崩猝灭现象.     

痕量葡萄糖的双酶催化荧光分析

在HAe-NaAc缓冲溶液中,葡笱糖氧化酶(GOD)催化葡萄糖与溶解氧反应牛成H2O2;辣根过氧化物酶(HRP)催化H2O2氧化过量的KI生成I3-,I3-分别与罗丹明S(RhS),罗丹明6G(Rh6G),丁基罗丹明B(b-RhB),罗丹明B(RhB)结合形成缔合物微粒,使得4体系分别在556,556,584和584 nm处的荧光峰强度线性降低.在最佧条件下,葡萄糖的浓度分别在0.083～9.99,0.17～8.33,0.33～8.33,0.33～9.99μmol·L-1范围内与RhS,Rh6G,b-RhB,RhB四体系的荧光猝灭强度呈良好的线性关系,其回归方程、相关系数、检出限分别为△F=40.0c+3.0,△F=23.9c+8.1,△F=25.6c+4.2,△F=18.4c+0.8:0.995 1,0.997 3,0.996 0,0.996 5;0.059,0.17,0.21,0.16μmol·L-1.RhS催化体系最灵敏、稳定,将其用于人血清中葡萄糖的检测,结果满意.     

水杨酸与牛血清蛋白相互作用的荧光光谱研究

应用荧光光谱研究了水杨酸与牛血清蛋白 (BSA)分子间的相互作用。研究表明 :水杨酸对BSA内源荧光的猝灭机制属于形成化合物所引起的静态猝灭 ,猝灭常数Ksv 为 1 0 97× 10 4 (mol·L- 1 ) - 1 ;水杨酸与BSA反应的结合常数为 7 377× 10 4 ,结合位点数为 1,当水杨酸浓度较低 (摩尔比小于 1∶1)时 ,它与Trp残基或其附近基团结合但并不引起Trp残基微环境的改变 ;根据F rster非辐射能量转移理论 ,计算了授体 受体间的结合距离和能量转移效率     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.